From 33894c367dbd5bd3ec5b26c643ca022798226dd9 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Fri, 23 Mar 2018 19:15:37 +0100 Subject: netfilter: nf_flow_table: add missing condition for TCP state check Avoid looking at unrelated fields in UDP packets Signed-off-by: Felix Fietkau Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_flow_table_ip.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c index 692c75ef5cb7..82451b7e0acb 100644 --- a/net/netfilter/nf_flow_table_ip.c +++ b/net/netfilter/nf_flow_table_ip.c @@ -15,11 +15,14 @@ #include #include -static int nf_flow_tcp_state_check(struct flow_offload *flow, - struct sk_buff *skb, unsigned int thoff) +static int nf_flow_state_check(struct flow_offload *flow, int proto, + struct sk_buff *skb, unsigned int thoff) { struct tcphdr *tcph; + if (proto != IPPROTO_TCP) + return 0; + if (!pskb_may_pull(skb, thoff + sizeof(*tcph))) return -1; @@ -248,7 +251,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb, return NF_DROP; thoff = ip_hdr(skb)->ihl * 4; - if (nf_flow_tcp_state_check(flow, skb, thoff)) + if (nf_flow_state_check(flow, ip_hdr(skb)->protocol, skb, thoff)) return NF_ACCEPT; if (flow->flags & (FLOW_OFFLOAD_SNAT | FLOW_OFFLOAD_DNAT) && @@ -460,7 +463,8 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb, if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu))) return NF_ACCEPT; - if (nf_flow_tcp_state_check(flow, skb, sizeof(*ip6h))) + if (nf_flow_state_check(flow, ipv6_hdr(skb)->nexthdr, skb, + sizeof(*ip6h))) return NF_ACCEPT; if (skb_try_make_writable(skb, sizeof(*ip6h))) -- cgit v1.2.3